The present invention relates to an apparatus for guiding a vehicle, specifically a map display which scales the display according to the distance between a start point and a finish point.
Presently, devices for guiding a vehicle, are provided with a display screen-on which can be displayed, among other things, a specified portion of a map, with an input and control unit among other things for choosing a display scale and for requesting a route sweep. The present device has a processor provided with software, so as to manage the display and among other things define the map portion displayed. The processor has instructions for moving the map portion displayed from a start point to a finish point.
The present guidance devices carry out a route sweep in the course of a procedure for guiding a vehicle, according to which a specified portion of a map is displayed on a screen, a display scale is chosen, and the map portion displayed is moved from a start point to a finish point.
Such a device for guiding a vehicle is known from document DE-OS 195 16 647 (B.M.W). According to this document, the map portion depicted is moved so as to follow the vehicle and the scale is magnified automatically when the speed of the vehicle is lower. However, the present device suffer from scaling problems encountered while performing the route sweep. Thus there is a need to optimize the running of a route sweep.
One embodiment of the present invention is an apparatus for guiding a vehicle, provided with a display screen on which can be displayed, among other things, a specified portion of a map, with an input and control unit among other things for choosing a display scale and for requesting a route sweep. The apparatus has a processor provided with software, so as to manage the display and among other things define the map portion displayed. The processor has instructions for moving the map portion displayed from a start point to a finish point. In order to optimize the route sweep, the software furthermore has instructions for adjusting, independently of the position of the vehicle, the rate of sweep of the map portion displayed as a function of the display scale requested at the start and of the total distance to be swept, and instructions for varying the scale as a function of the instantaneous rate of sweep.
Particularly embodiments of the apparatus include instructions for calculating the maximum so-called cruising rate desirable to obtain a short sweep time. The processor may also include instructions for, starting from a specified scale, moving the map portion at an increasing rate in such a way as to arrive at the cruising rate after a predetermined time, instructions for carrying out the central part of the sweep at the cruising rate, and instructions for terminating the sweep of the map portion while reducing the rate.
The software may also include instructions for calculating the maximum so-called cruising rate desirable to obtain a short sweep time and instructions for, starting from a specified scale, moving the map portion at an increasing rate in such a way as to arrive at the cruising rate after a predetermined time, whilst modifying the scale so as to arrive after the same time at a scale which is compatible with the cruising rate, instructions for carrying out the central part of the sweep at the cruising rate with said compatible scale, and instructions for terminating the sweep of the map portion while modifying the rate and the scale again so as to return to the initial scale.
The software may also include instructions for modifying the scale in the tiers, and for enlarging it each time that the rate undershoots a predetermined threshold. The software may also include instructions for modifying the scale progressively as a function of the rate.
The invention also relates to a process for carrying out a route sweep in the course of a procedure for guiding a vehicle, according to which a specified portion of a map is displayed on a screen, a display scale is chosen, and the map portion displayed is moved from a start point to a finish point.
According to the process of the invention, the map portion displayed is moved, independently of the position of the vehicle, at a rate which depends on the display scale requested at the start and on the distance to be swept during the sweep, and the scale is slaved continuously to the sweep rate.
The process further includes the step of calculating the maximum so-called cruising rate desired to obtain a short sweep time, starting from a specified scale. The map portion is moved at an increasing rate in such a way as to arrive at the cruising rate after a predetermined time. The central part of the sweep is then carried out at the cruising rate, and the sweep of the map portion is terminated while reducing the rate.
The map portion may be moved at an increasing rate in such a way as to arrive at the cruising rate after a predetermined time, whilst modifying the scale so as to arrive after the same time at a scale which is compatible with the cruising rate, the central part of the sweep is carried out at the cruising rat with said compatible scale, and the sweep of the map portion is terminated while modifying the rate and the scale again so as to return to the initial scale.
The software may include instructions for modifying the scale in tiers, and for enlarging it each time that the rate undershoots a predetermined threshold. The software may also include instructions for modifying the scale progressively as a function of the rate.
These aspects of the invention as well as other more detailed aspects will emerge more clearly by virtue of the following description of an embodiment constituting a non-limiting example of the invention. The accompanying drawings, which are incorporated in and constitute part of this specification, are included to illustrate and provide a further understanding of the method and system of the invention. Together with the description, the drawings serve to explain the principles of the invention.